Разложите на множители: 1) 81a^3- ab^2; 2) -8x^2- 16xy- 8y^2; 3) 5mn+ 15m- 10n- 30; 4) 256- b^4
81a^3- ab^2=a(9a-b)(9a+b) -8x^2- 16xy- 8y^2=-8(x+y)² 5mn+ 15m- 10n- 30=5m(n+3)-10(n+3)=(n+3)(5m-10) 256- b⁴=(16+b²)(4-b)(4+b)